Cloudy Hot Giants

Exoplanetary Scratchpad [SysBP Img]

Cloudy Hot Giants are giant planets so hot that silicate clouds form above the dark sodium haze causing the planets to be very bright. Here is a list of Cloudy Hot Jupiters that appear on Extrasolar Visions. This list may be updated to incorporate new science and discoveries. For a list of those exactly seen on Extrasolar Visions, see EV Cloudy Hot Giants.

Cloudy Hot Jupiters

• HD 75289 System - A cloudy Hot Jupiter around an yellow dwarf star.
• HD 88133 System - A cloudy Hot Jupiter around an yellow sub-giant star.
• Upsilon Andromedae System - Titawin (Upsilon Andromeadae) is a nearby (44 ly) multi-star system which is the first multiplanet system found around a main sequence star or a multi-star system. The main star around which the planets orbit is a yellow-white star somewhat younger than the sun and its companion is a red dwarf in a wide orbit. It is one of the most well studied non-transiting star systems. Roaster Saffar (b, 0.05 au, 0.62 MJ, e=0.013, and the nearest true Hot Jupiter to Earth) is nicknamed the Fire and Ice Planet because it is hot on one side and cold on the other. The hottest parts of the planet are near the trailing side terminator at the equator, due to high velocity winds transporting heat to the night side. This is 80deg offset from the starward pole and a much greater offset than other observed hot Jupiters. This threw astronomers off and caused them to doubt the wind-theory, though later observations of other planets have shown that winds indeed can travel fast enough to cause this. Stability studies and observations suggest its diameter is 1.8 DJ, rather large for a planet its age. The middle planets Samh (c, 0.83 au, 1.8 MJ, initially thought to possibly be a brown dwarf star, e=0.224) and Majriti (d, 2.5 au, 10.2 MJ, e=0.26) have had their inclinations and masses determined with astrometry, the first determination of relative inclinations of exoplanets. They are very eccentric and highly inclined to each other (30 deg). Planet scattering was thought to be a source until the outermost planet was discovered. This is planet e (5.2 au, 1.05 MJ, e = 0.005), which is the most Jupiter-like exoplanet known, and is in 3:1 resonance with planet d. Planet c is in the habitable zone, though any habitable moons would see drastic temperature swings. The star appears to have no Kuiper-belt like disc, perhaps due to its companion star sweeping away this material. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The star is named after an important city in Morocco that bridged the Spanish and Arab worlds. The planets are named after famous Andalusian astronomers.
• HD 187123 System -
• HD 149026 System - Ogma (HD 149026) is a yellow sub-giant star with the first known Saturn mass transiting planet, Smertrios. Also the first planet found with a dense core, leading credence to the core-accretion theory. Sometimes called a Super-Neptune, though it is not known if its core is rocky or icy. Also the first TEP discovered smaller than Jupiter. It was revealed to be as black as coal, twice as hot as any other known exoplanet, and hotter than some stars. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The star is named after a Celtic god of eloquence, writing, and great physical strength, while the planet was named after a Gallic deity of war.
• 51 Pegasi System - The star called 51 Pegasus is now known as Helvetios. Contains the first exo-planet around a normal star discovered and the first "Hot Jupiter" found, which is nicknamed "Bellerophon", and now called Dimidium. Star is about 50 ly located in the square of Pegasus, a G5 star somewhat larger and more massive than the Sun. The planet's discovery was incompatible with planetary system formation models, so they were tweaked to allow for planetary migration. It was also initially thought to be an anomaly or the stripped down core of a brown dwarf. Found to have supersonic winds that caused the eternal night-side hemisphere to be as hot as the day-side one. During its 20th anniversary, this planet became the first one's whose reflected visible light was detected. The technique involved looking at a star's visible spectrum, and then detecting a faint reflection of this spectra. Its actual mass (0.46 MJ) and inclination (9deg) were obtained as a result. The planet seems to have a larger radius and bright surface, rather typical for hot jupiters. One of the first 20 exoplanet systems allowed to be given common names by the IAU. The star's name is Latin for a Celtic tribe that lived in Switzerland (the place where its planet was discovered) during the middle ages. The planet's name is Latin for "half" due to the fact its minimum mass is half as massive as Jupiter's.
• HD 83443 System - A cloudy Hot Jupiter around an orange dwarf star.
• HD 76700 System - A cloudy Hot Jupiter around an yellow dwarf star.
• Tau Bootis System - Contains one of the first four discovered Hot Jupiters, which was one of the largest, hottest, closest in (P = 3.3d, a = 0.05) of the earlier discovered ones and the closest known at the time and is today one of the brightest planets known. It was immediately recognized to have tidally locked its star's rotation period. The star (also known as HR 5185) is nearby (50 ly), 1.5 times as massive as the sun. The planet does not transit its star, but is one of the brightest planets known. Several attempts to detect light were declared, but then refuted. In one such attempt by British astronomers, it was nicknamed the "Millenium Planet", and light was thought to have been detected (thought to be a first) by subtracting its star's light, giving an inclination of 29deg, mass of 8 MJ, and size of 1.8 RJ, and blue-green color. NASA's Spitzers later was thought to have detected it (again, a believed first, considering visually detected ones were planetary "candidates"). It was finally detected later by observing CO lines produced by reflected light through its atmosphere, yielding a mass of 6 MJ and inclination of 44F. Water was later also detected in its atmosphere in the near infra-red, the first for any non-transiting exo-planet. The temperature was unexpectedly found to be cooler at the upper levels, unlike many other hot Jupiters (strong ultraviolet radiation are thought to destroy the compounds responsible for creating thermal inversions in this case). The star was the first to have its magnetosphere detected (which envelopes the planet) and also the first known to magnetically flip like the Sun (flips once every Earth year, vs the Sun's 11 years). One of the first 20 exoplanet systems allowed to be given common names by the IAU, but the only one whose chosen name was rejected because it did not conform to IAU's naming standards.
• GSC 02652-01324 System - Contains the first transiting exoplanet discovered with the TrES amateur equipment and second transiting exoplanet close enough to have its atmosphere studied. It is the first Hot Jupiter that had the expected radius. Was the one of the first two exoplanets to have its light separated from its host star. Has a cloud or torus of particles around it. Tidal heating is predicted due to its eccentric orbit, but this has not seem to have inflated its radius.
• HD 209458 System - Has first discovered transiting planet which was nicknamed Osiris due to the (first detected) comet-like tail detected and the first exoplanet around a normal star to have its mass directly measured. Also the first Inflated Hot Jupiter found. The planet may be losing its outer atmosphere, or magnetism may prevent the ions from escaping. They detected water in its atmosphere (they had failed earlier), the first time this has been done for any exoplanet. 2nd Exoplanet with detected organic compounds; like HD 189733b, it has water and carbon dioxide, but it has a lot more Methane. Was one of 2 planets to have light directly taken and thus their temperatures read (over 1000K). Tracking carbon molecules with dopplar spectrometry caused it to be the first exoplanet detected to have winds, which are raging at 5,000 to 10,000 km/h. This is believed to cause hotspots to appear at terminators rather than at the star-ward facing point. Had one of the strongest water detection of the 5 exoplanets contrasted by Hubble in 2013, though still less intense than expected, probably due to dust clouds or a haze blocking its detection.
• HD 46375 System - An orange subgiant around which the larger of the first two Saturnians discovered (79 Ceti b was the other one) orbits, which was the first "Epistellar Saturn" discovered.

Eccentric Cloudy Hot Jupiters

• HD 38529 System - Subgiant star with a cloudy Hot Jupiter, Brown Dwarf, and Red Dwarf companion. Simulations showed that Earth-sized planet could exist between the planet and brown dwarf, but that an asteroid belt can be expected there instead.